This invention relates to mass airflow sensors that are used in airbodies of internal combustion engines.
In state-of-the-art electronically controlled fuel systems for automotive internal combustion engines, the measurement of airflow that is inductd into the engine's intake system is an input to the engine electronic control unit (ECU). One way of obtaining this measurement is by means of a mass airflow sensor located in a by-pass venturi in the airbody. In order to be acceptable, a mass airflow sensor must be able to pass a required dust test. For example, the sensor must be able to withstand a certain number of hours of dust flow at a certain number of grams of dust per hour. One problem is that a silicon mass airflow sensor is very susceptible to damage from dust particles traveling at high rates of speed.
The present invention provides a solution to this problem so that the potential for damage due to dust that is entrained in the airflow is significantly lessened. The solution comprises a deflector, or shield, that is placed upstream of the sensor and functions to shield the sensor from direct impact by large particles of dust, yet allowing smaller, less damaging particles to flow over the sensor. The placement of the deflector still allows the sensor to operate in an accurate manner for measuring airflow. The deflector is easy to fabricate and to assemble to the airbody so that it is quite cost-effective.
Other features and advantages of the invention, along with those just mentioned, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a preferred embodiment of the invention according to the best mode contemplated at the present time for carrying out the invention.